• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.86-91
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• 2015

The MPPO (3-methyl-1-phenyl-2-phospholene-1-oxide) was prepared by using various polymerization inhibitors such as BHT (2,6-di-tert-butyl-4-methylphenol), TBC (4-tert-butylcatechol), and copper stearate. The MPPO was confirmed by the analysis using FTIR, $^1H$-NMR, and GC/MS regardless of the type of inhibitors. The yield of MPPO increased with the increase of reaction time, whereas the purity of MPPO decreased slightly. The yield and purity of MPPO increased with temperature, but the MPPO prepared by using copper stearate as a polymerization inhibitor exhibited no changes in the purity. The amount of inhibitors had no effect on the yield of MPPO. The purity of MPPOs increased with the amount of inhibitors, but the MPPO prepared by using BHT showed no changes of the purity. We found that the MPPO prepared by using copper stearate exhibited the highest catalytic activity for diphenylcarbodiimide synthesis.

• Journal of Powder Materials
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• v.19 no.6
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• pp.429-434
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• 2012

With increase in operating temperature of gas turbine for higher efficiency, it is necessary to find new materials of TBC for replacement of YSZ. Among candidate materials for future TBCs, zirconate-based oxides with pyrochlore and fluorite are prevailing ones. In this study, phase structure and thermal conductivities of $(La_{1-x}Gd_x)_2Zr_2O_7$ oxide system are investigated. $(La_{1-x}Gd_x)_2Zr_2O_7$ system are comprised by selecting $La^{3+}/Gd^{3+}$ as A-site ions and $Zr^{4+}$ as B-site ion in $A_2B_2O_7$ pyrochlore structures. With powder mixture from each oxide, $(La_{1-x}Gd_x)_2Zr_2O_7$ oxides are fabricated via solid-state reaction at $1600^{\circ}C$. Either pyrochlore or fluorite or mixture of both appears after heat treatment. For the developed phases along $(La_{1-x}Gd_x)_2Zr_2O_7$ compositions, thermal conductivities are examined, with which the potential of $(La_{1-x}Gd_x)_2Zr_2O_7$ compositions for TBC application is also discussed.

• Korean Journal of Head & Neck Oncology
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• v.16 no.2
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• pp.201-205
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• 2000

Objectives: Despite of high prevalence of tuberculosis in Korea, thyroid tuberculosis is very rare and only a few records are available. This study was carried out to evaluate the clinicopathologic characteristics of thyroid tuberculosis and to find out optimal therapeutic strategies for these lesions. Materials & Methods: From Jan. 1986 to July. 2000, of 5,493 patients who were underwent thyroidectomy, only 8(0.14%) had discovered to have thyroid tuberculosis. The medical records of them were analyzed retrospectively. Results: There were one man and seven women with a mean age of 40.3 years. Only one had tuberculosis sequalae on chest X-ray and two had past history of tuberculous lymphadenitis. However, none of them had symptomatic pulmonary tuberculosis. Most frequent symptom was palpable neck mass. The preoperative U/S, CT and FNAB failed to diagnose thyroid tuberculosis. The pathologic reports were chronic granulomatous thyroiditis with caseous necrosis in all the cases and AFB stain was positve in 5 cases. All cases were successfully treated by surgical resection and anti-Tbc. medications. Conclusions: The incidence of thyroid tuberculosis was extremely low and most of them have been presented as a palpable neck mass especially in relatively young-aged female patients. Although any diagnosis for thyroid tuberculosis prior to microscopical study of tissue removed at operation was not yielded, the preoperative diagnostic workups will be available with experience. Surgical resection and anti- Tbc medication would be the choice in the management of thyroid tuberculosis.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.462-469
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• 2009

The aim of this study was to develop a portable electronic nose system for freshness measurement of stored pork. An electronic nose system was constructed using seven different MOS sensor array. To determine the quality change of pork with storage time, the samples were divided into ten groups in terms of storage time with an increment of 2 day up to 19 storage days. GC-MS, total bacteria's count (TBC), thiobarbituric acid reactive substance (TBARS), and pH analyses as well as the analysis of the electronic nose system measurement were performed to monitor the freshness change of the samples. To investigate the performance of the electronic nose system for detecting the change of freshness of pork, the acquired signal values of the system were compared with those of GC-MS, TBC, TBARS, and pH analysis values. According to principal component analysis (PCA) and linear discriminant analysis (LDA) with the signals of the electronic nose system for the pork samples, the sample groups were clearly separated into two groups of 1-9 days and 11-19 days, and four groups of 1-3 days, 5-9 days, 11 days, and 13-19 days respectively. The results show that the electronic nose system has potential for evaluating freshness of pork.

• Journal of Powder Materials
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• v.18 no.6
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• pp.568-574
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• 2011

As operating temperatures of engines or turbines continually increase for higher efficiency, significant amounts of researches have been focused on finding new materials, which would be alternatives to conventional yttria-stabilized zirconia (YSZ) for thermal barrier coatings (TBCs). In this study, phase evolution and thermo-physical properties of $La_2(Zr_{1-x}Hf_x)_2O_7$ pyrochlore systems are investigated for TBC applications. $La_2(Zr_{1-x}Hf_x)_2O_7$ systems are comprised by selecting $La^{3+}$ as A-site ions and $Zr^{4+}/Hf^{4+}$ as B-site ions in $A_2B_2O_7$ pyrochlore structures. For the developed phases in $La_2(Zr_{1-x}Hf_x)_2O_7$ compositions, thermo-physical properties such as thermal conductivity, thermal expansion coefficient are examined. The potential of these $La_2(Zr_{1-x}Hf_x)_2O_7$ compositions for TBC application is also discussed.

• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.76-81
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• 2004

From September 1, 2003 to November 30, 2004, 20 mineral water wells were selected for some area in east Europe and the study on their water quality was analized. It revealed that mineral water contained considerable quantity of magnesium ions which helps the smooth activities of vascular muscles, nervous systems and protects skins from allergic reactions. It also lowers cholesterol level and contains high concentration of calcium ions which is one of the vital components of teeth and bone like phosphorus. Thus it is concluded that it is not qualified as boiler feed water as it has overall high degree of hardness by the presence of four times content of $Mg^{2+}\;and\;Ca^{2+}$.

• Journal of the Korean institute of surface engineering
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• v.31 no.1
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• pp.12-23
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• 1998

The Thermal Barrier Coating(TBC) has been used to improve the heat barrier and tribological properties of the aircraft engine and the automobile engine in high temperature. Especially, the high temperature tribological propertied of the cylinder haed and the piston crown of diesel engine was emphasized. Therefore, the purpose of this work was to evaluate the microstructure, tribological propeer in high tempearmal shock resistance and bonding strength of five layer functionally gradient TBC for the applications. The five layerwere composed with 100% ceramic insulating later, 75(ceramic):25 (metal) layer, 50:50 layer, 25:75 layer and 100% metal bonding layer to redude the thermal stress. the YSL and MSL poweders were the insulation ceramics powers. The NiCrAly, Inconel625 and SUS powders were the bonding and mixingg powders for plasma spray process. According to the result of high temperature wear test, the wera resistance of YSZ/NiCrAlY siytem was most out standing at 600 and $800^{\circ}C$. At $400^{\circ}C$, the wear resistance of YSZ/Inconel system was better than others. Wear volume at other temperature because of the low temperature degration of zirconia. The thermal shock mechanism of 5 later is the vertical crack gegration in insulating layer. this means that the initial cracks were generated in the top layer, and then developed into the composite layers during thermal shock test. Finally, these cracks werereached to the interface of coating and substrate and also, these vertioal cracks join with the horizontal cracks of the each layers. The bonding strength of YSZ/NiCrAlY and YSZ/Inconel 5 layer system is better than other 5layer systems. The theramal shock resistance of thermal barrier coating s with 5 layer system is better than that of 3 layers and 2 layers.

• Journal of Powder Materials
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• v.22 no.6
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• pp.413-419
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• 2015

Lanthanum zirconate, $La_2Zr_2O_7$, is one of the most promising candidates for next-generation thermal barrier coating (TBC) applications in high efficient gas turbines due to its low thermal conductivity and chemical stability at high temperature. In this study, bulk specimens and thermal barrier coatings are fabricated via a variety of sintering processes as well as suspension plasma spray in lanthanum zirconates with reduced rare-earth contents. The phase formation, microstructure, and thermo-physical properties of these oxide ceramics and coatings are examined. In particular, lanthanum zirconates with reduced rare-earth contents in a $La_2Zr_2O_7-4YSZ$ composite system exhibit a single phase of fluorite or pyrochlore after fabricated by suspension plasma spray or spark plasma sintering. The potential of lanthanum zirconate ceramics for TBC applications is also discussed.

• Journal of Powder Materials
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• v.20 no.6
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• pp.460-466
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• 2013

4 mol% Yttria-stabilized zirconia (4YSZ) coatings with $200{\mu}m$ thick are fabricated by Electron Beam Physical Vapor Deposition (EB-PVD) for thermal barrier coating (TBC). $150{\mu}m$ of NiCrAlY based bond coat is prepared by conventional APS (Air Plasma Spray) method on the NiCrCoAl alloy substrate before deposition of top coating. 4 mol% YSZ top coating shows typical tetragonal phase and columnar structure due to vapor phase deposition process. The adhesion strength of coating is measured about 40 MPa. There is no delamination or cracking of coatings after thermal cyclic fatigue and shock test at $850^{\circ}C$.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.3
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• pp.245-251
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• 2013

The purpose of this study was to investigate the effects of fluvastatin on the pharmacokinetics of repaglinide in rats. The effect of fluvastatin on P-glycoprotein and CYP3A4 activity was evaluated. The pharmacokinetic parameters and blood glucose concentrations were also determined after oral and intravenous administration of repaglinide to rats in the presence and absence of fluvastatin. Fluvastatin inhibited CYP3A4 activity in a concentration-dependent manner with a 50% inhibition concentration($IC_{50}$) of 4.1 ${\mu}M$ and P-gp activity. Compared to the oral control group, fluvastatin significantly increased the AUC and the peak plasma level of repaglinide by 45.9% and 22.7%, respectively. Fluvastatin significantly decreased the total body clearance (TBC) of repaglinide compared to the control. Fluvastatin also significantly increased the absolute bioavailability (BA) of repaglinide by 46.1% compared to the control group. Moreover, the relative BA of repaglinide was 1.14- to 1.46-fold greater than that of the control. Compared to the i.v. control, fluvastatin significantly increased the $AUC_{0-{\infty}}$ of i.v. administered repaglinide. The blood glucose concentrations showed significant differences compared to the oral controls. Fluvastatin enhanced the oral BA of repaglinide, which may be mainly attributable to the inhibition of the CYP3A4-mediated metabolism of repaglinide in the small intestine and/or liver, to the inhibition of the P-gp efflux transporter in the small intestine and/or to the reduction of TBC of repaglinide by fluvastatin. The study has raised the awareness of potential interactions during concomitant use of repaglinide with fluvastatin. Therefore, the concurrent use of repaglinide and fluvastatin may require close monitoring for potential drug interactions.